Producing a defined volume or mass of a sample for subsequent testing is an important initial step in many settings, e.g., in the food industry, for environmental monitoring, in medicine, etc. For instance, in the medical clinic, laboratory examination of fecal samples is an important component of some diagnoses. In these cases, stool specimens are taken from a patient and examined for conditions relative to the health or ailment of the patient. As specific examples, physicians and clinicians often test stool samples as a component of testing for colon or rectal cancer or pre-cancerous conditions, or to identify bacteria or viruses that may be involved in an infection. Additionally, some diagnostics require isolating and assaying nucleic acids, proteins, fats, or other analytes present in the stool specimen. Such tests for viruses, bacteria, nucleic acids, proteins, and fats are also performed on other types of samples, e.g., food and environmental samples. Consequently, acquiring a sample from a specimen (e.g., a stool specimen) is the first step in sample processing for many tests (e.g., the medical diagnostic analysis of feces). As the first step in such analyses, the sample integrity, the reproducibility of the sample size, the reproducibility of the means and method used to acquire the sample, and the efficiency of sample preparation are all critically important for the subsequent processing and testing steps.
The collection of some samples (e.g., fecal samples) for testing presents particular challenges, both to the individuals providing such samples as well as to the technicians testing them. Samples obtained away from a medical facility or testing laboratory must be mailed or otherwise transported and, when received at a laboratory, need to be handled without exposing technicians to such sample material. The collected samples further need to be appropriately tested. There remains a need for better methods and devices for collecting such samples, transferring the samples to test devices, and performing assays, in particular to facilitate the transfer of a sample to a test device while minimizing the possibility of exposure of a technician to the sample.
Conventional sample collection devices and techniques have used, for example, buckets and spoons to prepare a sample from a larger specimen. For instance, for medical diagnostic tests of stool samples, entire stool specimens have been collected in buckets with lids, to which a bulk quantity of stabilization buffer is added. Spoon-type devices are used to break off samples from a specimen, which samples are then placed in a jar or tube with buffer. However, these and other conventional collection methods have proven unsatisfactory for a number of reasons. For example, collecting whole specimens in buckets does not provide samples of reproducible size or volume suitable for accurate and/or automated downstream processing. Manual weighing, aliquoting and/or dilution are required prior to processing, but these manipulations are not efficient, accurate, or sufficiently reproducible. Preparing a sample from a specimen with a spoon device is not as reproducible as using a fixed-volume device. Using a spoon also requires applying a downward pressure on the specimen. If the specimen has been collected in a disposable receptacle, e.g., a collection paper, downward pressure during sampling increases the probability that the underlying collection paper will fail. Moreover, using a spoon requires the person collecting the sample to be close to the specimen from which the sample is to be taken, increasing the risk of exposure. Moreover, most conventional devices for sample capture are non-intuitive to use, position the sample collection portion of the device near a user-manipulable portion of the device, and/or make it difficult for the user to place the collected sample into a container, such as a collection tube.